FIELD OF THE INVENTION
The invention relates to a circuit configuration for generating a reference potential, including a first transistor with an emitter connected to a ground potential and a base and a collector connected to one another; a second transistor with a base connected to the base of the first transistor; a first resistor connected between the collector of the first transistor and an output terminal for picking up the reference potential; a second resistor connected between the collector of the second transistor and the output terminal; a third resistor connected between the emitter of the second transistor and the ground potential; a third transistor with a base connected to the collector of the second transistor and an emitter connected to the ground potential, and a controlled current source connected between a supply potential and the output terminal and coupled on the input side to the collector of the third transistor.
One such circuit configuration, which is also known as a bandgap reference is known, for instance, from the book by Paul R. Gray and Robert G. Meyer, entitled: Analysis and Design of Analog Integrated Circuits, Second Edition, John
Wiley and Sons, 1984, pp. 293-296 and from Published European Patent Application 0 411 657 A1, and is often used in integrated circuits as an internal reference voltage source. A frequency-compensated bandgap reference is also described in UK Patent Application GB 2 256 949 A.
In the future, it will become increasingly important in integrated circuits for the circuits to be able to be turned on and off through an external terminal, in order to save current. Turning them off should happen as fast as possible, in order to enable effective reduction in the current consumption and thus the power loss. The turn-on time should be kept as short as possible as well, in order to put the circuit into its operating state within the shortest possible time. A further important criterion of circuit configurations for generating a reference potential is their noise behavior. That can be favorably affected through the use of capacitors for bandgap limitation, which filter out the noise at high frequencies. However, those provisions lengthen the turn-on and turn-off times of the respective circuit.